Method of yarn severing in circular knitting machines



y 1, 1963 P. A. MAHLER 3,090,216

METHOD OF YARN SEVERING IN CIRCULAR KNITTING MACHINES Filed July 12, 1960 2 Sheets-Sheet 1 J6\---- 25 FIG I M 35 INVENTOR: 2/ PETER A. MAHLER ATTYS,

3,090,216 METHOD OF YARN SEVERING IN CIRCULAR KNITTING MACHINES Filed July 12, 1960 P. A. MAHLER May 21, 1963 2 Sheets-Sheet 2 1 INVENTOR. PETER A. MAHLER ATTYS,

United States Patent METHGD 0F YARN SEVERING IN (CIRCULAR KNHTTHJG MACHWES Peter A. Mahler, Philadelphia, Pa., assignor to Singer- Fidelity, Inc, Philadelphia, Pin, a corporation of Delaware Filed July 12, 1960, Ser. No. 42,333 3 Uaims. (Cl. 65140) The present invention relates to circular knitting inachines, and has particular application to a method for severing the knitting yarns closely adjacent the needle circle in a multifeed machine.

The present invention is an improved method which may be used with yarn trimmers for rotary circular knitting machines in which a cutter element at a fixed location cooperates with a toothed ring mounted on the rotary dial of the knitting machine within and closely adjacent the needle circle. Such cutting devices have not been entirely satisfactory on multifeed machines in which yarns are inserted into and withdrawn from action selectively at the different feed stations. The primary difiiculty resides in the proper locking-in of the free yarn end which is severed when the knitting of yarn at one station is terminated or initiated, inasmuch as a cutter of the type described, does not provide a tail of yarn of sufficient length to prevent its raveling prior to being knitted-in and interlocked with the knitted loops of the subsequent course.

With the foregoing in mind, the present invention provides an improved method of severing yarn ends in a multifeed circular knitting machine in which the cutting device operates to sever the yarn closely adjacent the needle circle at a position wherein the severed end of yarn is entrapped in the hook of the needle by the latch thereof, the cutting device being inoperative to cut the yarn end until it has been trapped in the needle hook by the latch.

More particularly, the present invention provides an improvement wherein the cutting occurs at a point relative to the needle cams following the point where the cams lower the needles to an extent as to raise the latches.

More specifically, in accordance with a preferred embodiment of the present invention, the cutting mechanism which severs the yarn from one feed station, is located in registry with the stitch cam at the next subsequent feed station so as to cut the yarn end from the first feed station concurrently with the elevation of the latch of the needle at the subsequent feed station whereby the latch entraps the yarn end in the hook of the needle as the needle is depressed to the stitch-draw level.

The preferred embodiment of the present invention permits the cutting element to be located at the subsequent feed station in a position where it is inoperative upon the yarn ends being inserted and withdrawn at the subsequent feed station but is fully effective to sever the yarns from the first-mentioned feed station.

All of the objects of the present invention are more fully set forth hereinafter with reference to the accompanying drawings which illustrate circular knitting machines in accordance with the present invention, and wherein:

FIG. 1 is a fragmentary plan view showing the dial of a multifeed knitting machine along with a main and auxiliary feed station, certain operating elements being omitted for the purpose of clarity of illustration of the present invention;

. FIG. 2 is an enlarged fragmentary view in side elevation of the dial, as seen from the line 22 of FIG. 1;

FIGS. 3 and 5 are fragmentary sectional views through the dial as taken on the lines 3-3 and 55 respectively of FIG. 1;

FIG. 4 is a fragmentary perspective view of a cutter element such as shown in FIG. 2;

FIG. 6 is a view at a reduced scale similar to FIG. 2 and showing in broken lines the positions of the needle cams relative to the position of the cutting element shown in FIG. 2;

FIG. 7 is a fragmentary perspective view illustrating the operation of the cutter;

FIG. 8 is a view in side elevation of the elements shown in FIG. 7, and

FIG. 9 is a fragmentary sectional view taken on the angled section line 9-9 of FIG. 1 with a yarn shown in full lines to illustrate the operation of the suction tube.

Referring to the drawings, the knitting machine illustrated in FIGS. 1 to 9 inclusive comprises a circle of needles 15 mounted for rotation in a needle cylinder 16 which carries a ring of sinkers 17 therewith (see FIG. 3). Within the needle circle 15, a rotary dial 21 is mounted for rotation with the needle cylinder 16. The dial 21 mounts a series of bits 22 for radial projection therefrom and also mounts an annular ring 23 which, as shown in FIGS. 1, 2, and 4, is toothed about its periphery to provide a series of teeth 24 having radial leading faces 25 terminating at their upper edge in a cutting edge 26. A stationary dial cap 31 is mounted on the dial 21 and carries cutting elements and guide pins as more fully set forth hereinafter.

Surrounding the needle circle 15 is a latch ring 32 which is interrupted at a plurality of locations by feed stations, in the present instance designated 33 and 34. The feed station 33 comprises a throat plate 35 and a plurality of feed fingers 36. The feed station 34 comprises a throat plate 37 and a plurality of feed fingers 38. In accordance with the usual practice, the needle cylinder and dial are rotated and the feed fingers 36 and 38 are operated in timed relation to the needle cylinder 16 to insert yarns into and withdraw yarns out of action by the conventional pattern mechanism (not shown) including a pattern drum and pattern chain. Suction tubes 39 and 40 respectively overlie the dial to tension the yarns which are out of action and to withdraw from the dial the yarn ends which are severed as described more fully hereinafter.

In accordance with the invention, a cutter mechanism is provided for each feed station, as designated generally at 28 and 29. Each of the cutter mechanisms 28 and 29 cooperates with the cutting edges 26 of the toothed ring 23 to sever the yarn engaged over the edge 26. The cutter mechanism 28 for the feed station 33 operates to out only the yarns which are inserted or withdrawn at the feed station 33 and is inoperative to cut the yarns inserted and withdrawn at the feed station 34. By the same token, the cutter mechanism 29 for the feed station 34 is operative to out only the yarns inserted and withdrawn by the feed fingers 3S and is inoperative to sever the yarns inserted and withdrawn by the feed fingers 36 at the feed station 33.

In the embodiment of the invention illustrated in FIGS. 1 to 9 inclusive, the cutter mechanism 28 comprises a spring blade 44 mounted on a bracket 45 which in turn is secured to the dial cap 31. The blade 44 at its free extremity terminates in a downturned leg 46 which rides on the upper surface of the teeth 24 of the toothed ring 23. As shown in FIG. 1, the leg 44 engages the toothed ring 23 at a point slightly in advance of the feed station 34, so that the yarns inserted and withdrawn at the feed station 34 are not subject to severing by the leg 46 of the blade 44.

In the operation of the cutter mechanism 28, the yarn Y-l that is withdrawn from action, for example by the feed finger 36 2, is carried by the needle circle 15 and the toothed ring 23 into engagement with the leg 46 of the '3 cutter 44. As shown in MG. 1, the yarn Y-l passes over the dial cap in a generally straight-line path between the leg 46 of the cutter 44 and the withdrawn feed finger 38-2. As shown in FIG. 1, the yarn passes under the cutter blade 44 and bracket 45, under the outermost corner of the suction tube 39 under the hold-down wire 48 and upwardly to the elevated feed finger 36-2. When the leg 46 cooperates with the cutting edge 26 of the tooth, the yarn Y-l is severed and the suction in the tube 39 draws the severed end upwardly into the tube and the yarn Y-l will thereafter assume a position adjacent the other inactive yarns Y-Z extending from the inactive feed fingers 36 to the tube 39. It should be noted that the elongated form of the nozzle tube 39 positions the inactive yarns Y-Z away from the path of movement of the yarns Y-1 and Y-3 across the top of the dial, and therefore prevents any interference between the inactive yarns and the yarns being inserted and withdrawn;

A yarn Y-3 was inserted into action by the feed finger 36-1 prior to withdrawal of the yarn Y-l. The yarn Y-3 was inserted by actuating the feed finger 36-1 to draw the yarn downwardly from the tube 39 into the needle circle 15. it is noted that the cutter mechanism 29 is positioned below the inactive yarns Y-Z, so that there is no possibility of the latter mechanism severing the yarns. As the needle circle is rotated, it carries the yarn circumferentially around the dial cap, the suction in the tube 39 causing the yarn to assume a straight-line path between the tube 39 and the point of insertion of the yarn in the needle circle 15. FIG. 9 illustrates the yarn Y-S in an intermediate position adjacent the suction tube 39. As the needle circle rotates the point of engagement beyond the intermediate position, the end of the yarn Y-3 is carried into engagement with the depending leg 46 of the cutter blade 44, the yarn spanning from the cutting edge 26 of the tooth 24 under the blade 44 and into the suction tube 39. When the tooth 24 is advanced past the depending leg 46, the yarn end is severed and the severed terminal end of the yarn Y-3 is carried away by the suction tube 39, leaving a very small tail. Since the operation of the knitting machine provides an overlap between the withdrawn yarn end and the inserted yarn end, there is no substantial problem in providing an effective lock-in of the severed yarn ends, from the feed station 33, and the cutter mechanism 28 may be positioned at any location where it is inoperative upon the yarns inserted at the feed station 34, but is operative upon the yarns inserted or withdrawn at the feed station 33.

In accordance with the invention, the cutter mechanism 29 for the auxiliary feed station 34- is positioned at the next subsequent feed station in a position where the latches of the needles are in position to trap the severed yarn end within the hooks of the needles. To this end, the cutter mechanism 29 is positioned adjacent the main feed station 33. As shown in FIG. 2, the cutter mechanism 29 comprises a flat spring member 51 having at its free extremity a depending leg 52. which cooperates with and bears upon the teeth 24 of the ring 2-3. At its opposite end, the cutter member 51 is mounted in a bracket 52a having a yarn deflector 53 formed integrally therewith. The yarn deflector 53 insures that the yarns from the feed fingers 38 pass under the cutter element 51 so as to be severed by the engagement of the leg 52 with the teeth 24.

In the operation of the cutter 29, a shown in FIGS. 1 to 8, the yarn Y-d is shown being withdrawn from action by the feed finger 33-2. The yarn Y-5 has been inserted into action by the feed finger 38-3 and the yarn Y-6 is held out of action by the feed finger 38-1. As shown in FIG. 1, the yarns Y-4 and Y-6 pass under a hold-down wire 56 and are elevated above the level of the dial cap 31 by an elevator wire 57 (see FIG. 5) which reduces the drag on the yarn and assists the lifting of the yarn by the suction tube 41 the yarns passing around guide pins 58, 59, and 68 which prevent entanglement of the yarn with the mechanism on the dial. The yarn Y-6 is drawn up into the suction tube 4% and the yarn Y-4 continues around the dial, being guided by pins 61, 62 and 63 and is finally carried under the cutter element 51 by the needle circle 15 and the toothed ring 23. It is noted that a final group of needles designated 15-4 in FIGS. 1, 7, and 8 are not depressed to the stitch-draw level at the feed station 34, so that they carry the yarn Y-4 within their open books which receive the yarn Y-S at the feed station 33, thereby forming composite loops on the needles 15-4. This is more fully set forth in my copending application Serial No. 692,670, now US. Patent No. 2,987,900. As described in this patent, upon withdrawal of the yarn Y-4 from action, the yarn is engaged on all needles up to and including the selected group of needles 1-5-4 at the station 34. The yarn Y-4 is knit on the needles up to the group 15-4 at the station 34, and is knit on the needles of group 15-4 along with the yarn Y-3 at the subsequent feed station 33. The needles immediately following said selected needles are not elevated at the feed station 34, so as to avoid taking and knitting the yarn Y-4.

As shown in FIG. 6, the cutting leg 52 of the cutter element 51 is positioned in registry with the stitch cam 71? which depresses the needles 15 to the stitch-draw level. The needles 15 are conventional latch needles having a hook '71, and a latch 72 pivoted thereto. As the pivot point of the latch 72 passes from above to below the sinker level 17, the previously knit loop of the yarn Y-5 on the needles 15 raises the latch to close the hook 71 in conventional manner. As clearly shown in FIG. 8, the positioning of the leg 52 in registry with the stitch cam insures that the latch 72 is closed against the hook 71 when the yarn end Y-4- is severed. By this arrangement, therefore, the severed end of the yarn Y-4 is entrapped in the needle hook 71 and a proper lock-in of the trailing end of the yarn Y-4 is provided. Upon severance of the yarn Y-4, the suction tube 40 draws the severed unknit end of yarn away from the cutter element 51 and into the tube where it assumes a position adjacent the yarn Y-6.

A similar action occurs when the yarn Y-S is carried by the needle circle 15 and the toothed ring 23 into engagement with the cutter element 51. The yarn Y-5 at this point spans from the cutter element 51 around the guide pins 63, 62, and 61 and into the suction tube 40. When the yarn passes the depending leg 52 of the cutter element, it is severed and the severed end is withdrawn from the dial by the suction in the tube 40. The knit end of yarn, as was the case in connection with yarn Y-4, is trapped in the hook 71 of the needles 715 by the latches 72 and the positioning of the cutter element at the stitch cam of the subsequent feed station therefore insures proper locking-in of the yarn end. It is noted that prior to insertion of the yarn Y-5, the needles are not elevated at the feed station 34 until an initial group of needles designated 15-5 in FIG. 1 enter the station. When the selected needles enter the station, they are elevated to take yarn and are not depressed to the stitchdraw level at the station 34, so that they carry the yarn Y-S within their open hooks which receive the yarn Y-3 at the feed station 33. The needles following the selected needles 15-5 are also elevated at the station 34, but are also depressed to initiate knitting of an independent course at that station. This action is set forth more fully in my above-noted patent.

It is apparent that if desired, the cutter mechanism 29 may be positioned further along on the needle cam track if means is provided to insure that the cutter mechanism 29 does not sever the yarns inserted and withdrawn at the feed station 33. For the purposes of this invention, it is preferred to locate the cutting element 52 of the cutter 51 in registry with the stitch cam in the position where the needle latches 72 are elevated to close the hooks '71 of the needles and prevent escape of the severed yarn end from the hooks. By locating the cutting element 52 at this location, the yarn Y-3 which is inserted at the feed station 33 is drawn down into the teeth 24 of the ring 23 by the stitch cam 70 immediately after passing over the cutter blade 51.

If desired, operating levers controlled by the pattern mechanism of the knitting machine may be provided to raise the cutter blades 44 and 51 to disengage the legs 46 and 52 from the toothed ring 23 when there is no insertion or withdrawal of yarns at the respective feed stations 33 and 34.

While a particular embodiment of the present invention has been herein illustrated and described, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims.

I claim:

1. A method of knitting a circular-knit stocking comprising feeding a terminal end of one yarn to selected needles of a circle of needles having hooks and latches at one feed station, advancing said selected needles to a subsequent feed station with the one yarn in the hooks thereof, feeding a second yarn into the hooks of said selected needles at the subsequent feed station, actuating said selected needles at the subsequent feed station to close the latches against the hooks and entrap the one yarn in said hooks with the second yarn for the formation of composite loops, and severing the unknit terminal end of said one yarn following said actuation of the needles and while the latches thereof are closed at a point closely adjacent the needle circle, whereby the closed latches retain the one yarn in the hooks with the second yarn.

2. A method according to claim 1 wherein said terminal end of the one yarn is inserted into action at said one feed station immediately in advance of said selected needles, said end being severed at said subsequent feed station at a point in the needle circle in advance of said selected needles.

3. A method according to claim 1 wherein said terminal end of the one yarn is Withdrawn from action at said one feed station immediately following said selected needles, said end being severed at said subsequent feed station at a point in the needle circle following said selected needles.

References titted in the file of this patent UNITED STATES PATENTS 2,525,704 Miller Oct. 10, .1950 2,824,436 Stack et al Feb. 25, 1958 3,006,173 Shoaf Oct. 31, 1961 

1. A METHOD OF KNITING A CIRCULAR-KNIT STOCKING COMPRISING FEEDING A TERMINAL END OF ONE YARN TO SELECTED NEEDLES OF A CIRCLE OF NEEDLES HAVING HOOKS AND LATCHES AT ONE FEED STATION, ADVANCING SAID SELECTED NEEDLES TO A SUBSEQUENT FEED STATION WITH THE ONE YARN IN THE HOOKS THEREOF, FEEDING A SECOND YARN INTO THE HOOKS OF SAID SELECTED NEEDLES AT THE SUBSEQUENT FEED STATION, ACTUATING SAID SELECTED NEEDLES AT THE SUBSEQUENT FEED STATION TO CLOSE THE LATCHES AGAINST THE HOOKS AND ENTRAP THE ONE YARN IN SAID HOOKS WITH THE SECOND YARN FOR THE FORMATION OF COMPOSITE LOOPS, AND SEVERING THE UNKNIT TERMINAL END OF SAID ONE YARN FOLLOWING SAID ACTUATION OF THE NEEDLES AND WHILE THE LATCHES THEREOF ARE CLOSED AT A POINT COLSELY ADJACENT THE NEEDLE CIRCLE, WHEREBY THE 